The present invention relates to a fixing structure of a pulley unit for attaching the pulley unit to an auxiliary machine or the like with respect to a pulley unit provided with a one-way clutch.
Various auxiliary machines attached to an automobile engine are generally driven by a crank shaft of an automobile engine via a belt. Among auxiliary machines, for example, in the case of an alternator, as the number of revolutions of a crank shaft decreases, the power generating capacity also decreases. Responding to this, there is a technique that a one-way clutch is incorporated in a pulley unit that is attached to an alternator so that the number of revolutions of the rotor of the alternator is kept by inertial force to maintain the power generating efficiency when the number of revolutions of a crank shaft decreases.
In the case of such a pulley unit, for example when the pulley unit is attached to an alternator, since a one-way clutch is incorporated, the width in the shaft center direction becomes large, and thus the width in the shaft center direction of the whole apparatus including the alternator becomes large.
Therefore, the main object of the present invention is to provide a structure for fixing a pulley unit in which in the case where the pulley unit is attached to an auxiliary machine or the like, the width in the shaft center direction of the whole apparatus including the auxiliary machine and the pulley unit can be miniaturized.
Other objects, features, and advantages of the present invention will be apparent from the following description.
In summary a fixing structure of a pulley unit according to the present invention has a structure in which a rotary shaft is inserted into and supported by a central hole of a housing in a state where the rotary shaft is protruded from an end face of the housing and in which the pulley unit is attached to a part of the rotary shaft protruding from the central hole of the housing, wherein a housing side end portion of the pulley unit is inserted into an opening side area in the central hole of the housing so that an outer peripheral face of the housing side end portion of the pulley unit overlays an inner peripheral face of the opening side area in the central hole of the housing in a shaft center direction.
In the present invention, preferably, the outer peripheral face of the housing side end portion of the pulley unit and the inner peripheral face of the opening side area in the central hole of the housing oppose each other in the radial direction thereof via a fine gap forming a non-contact sealing part.